Why am I getting an error that Firefox is already running?

Description

You are trying to open up Firefox, but Firefox says that it is already running.

Cause

This is due to Firefox not closing out properly (Due to a crash, Power Outage, network dropping while on a network account machine). Firefox creates 'lock' files to make sure there is only one firefox application running.

Resolution

To fix this, you will need to do the following based on which OS you are on:

For Linux

Open up a terminal window (Using Terminal or Terminator)

In your home directory, there is a .mozilla directory, type 'cd .mozilla/firefox'

Type 'ls', you should see something like:

<a bunch of random characters>.default

Type 'cd <random characters>.default'

Type 'rm *lock' to remove the lock files.

For Mac

Open up a terminal windows (In the upper right hand corner with the magnifying glass, click on there and type 'terminal')